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Your search keyword '"Hwang, Kwang Yeon"' showing total 22 results
Start Over Author "Hwang, Kwang Yeon" Journal biochemical and biophysical research communications
22 results on '"Hwang, Kwang Yeon"'

21. Crystal structure of Legionella pneumophila type IV secretion system effector LegAS4.

Author

Son J, Jo CH, Murugan RN, Bang JK, Hwang KY, and Lee WC

Subjects
Amino Acid Sequence, Ankyrin Repeat, Bacterial Proteins genetics, Bacterial Proteins metabolism, Binding Sites, Crystallography, X-Ray, Histones genetics, Histones metabolism, Legionella pneumophila genetics, Legionella pneumophila metabolism, Models, Molecular, Molecular Sequence Data, Protein Interaction Domains and Motifs, Recombinant Proteins chemistry, Recombinant Proteins genetics, Recombinant Proteins metabolism, S-Adenosylmethionine chemistry, S-Adenosylmethionine metabolism, Structural Homology, Protein, Type IV Secretion Systems genetics, Type IV Secretion Systems metabolism, Bacterial Proteins chemistry, Legionella pneumophila chemistry, Type IV Secretion Systems chemistry
Abstract

The SET domain of LegAS4, a type IV secretion system effector of Legionella pneumophila, is a eukaryotic protein motif involved in histone methylation and epigenetic modulation. The SET domain of LegAS4 is involved in the modification of Lys4 of histone H3 (H3K4) in the nucleolus of the host cell, thereby enhancing heterochromatic rDNA transcription. Moreover, LegAS4 contains an ankyrin repeat domain of unknown function at its C-terminal region. Here, we report the crystal structure of LegAS4 in complex with S-adenosyl-l-methionine (SAM). Our data indicate that the ankyrin repeats interact extensively with the SET domain, especially with the SAM-binding amino acids, through conserved residues. Conserved surface analysis marks Glu159, Glu203, and Glu206 on the SET domain serve as candidate residues involved in interaction with the positively charged histone tail. Conserved surface residues on the ankyrin repeat domain surround a small pocket, which is suspected to serve as a binding site for an unknown ligand., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Published
2015
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22. Structural insights into the substrate recognition properties of beta-glucosidase.

Author

Nam KH, Sung MW, and Hwang KY

Subjects
Catalysis, Catalytic Domain, Cellobiose chemistry, Crystallography, X-Ray, Glucose chemistry, Metagenome, Protein Conformation, Soil Microbiology, Substrate Specificity, beta-Glucosidase genetics, beta-Glucosidase chemistry
Abstract

Beta-glucosidase enzymes (EC 3.2.1-3.2.3) hydrolyze sugars and are implicated in a wide spectrum of biological processes. Recently, we reported that beta-glucosidase has varied kinetic parameters for the natural and synthetic substrates [K.H Nam, S.J. Kim, M.Y. Kim, J.H. Kim, T.S. Yeo, C.M. Lee, H.K Jun, K.Y. Hwang. Crystal structure of engineered beta-glucosidase from a soil metagenome, Proteins 73 (2008) 788-793]. However, an understanding of the kinetic values of beta-glucosidase has not yet enabled the elucidation of its molecular function. Here, we report the X-ray crystal structure of beta-glucosidase with a glucose and cellobiose fragment from uncultured soil metagenome. From the various crystals, we obtained the pre-reaction (native), intermediate (disaccharide cleavage) and post-reaction (glucose binding) states of the active site pocket. These structures provide snapshots of the catalytic processing of beta-glucosidase. In addition, the intermediate state of the crystal structure provides insight into the substrate specificity of beta-glucosidase. These structural studies will facilitate elucidation of the architectural mechanism responsible for the substrate recognition of beta-glucosidase., (Copyright 2009 Elsevier Inc. All rights reserved.)

Published
2010
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